Renderer reading side of gamepad

content/browser/gamepad/gamepad_provider_unittest.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/memory/scoped_ptr.h"
 #include "base/process_util.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/system_monitor/system_monitor.h"
 #include "content/browser/gamepad/gamepad_provider.h"
 #include "content/common/gamepad_messages.h"
 #include "testing/gtest/include/gtest/gtest.h"
 

[darin (slow to review), 2011/11/30 18:34:37]

nit: A 'using WebKit::WebGamepads" might be nice here.

[scottmg, 2011/11/30 19:43:31]

Done.

 namespace {
 
 class MockDataFetcher : public gamepad::DataFetcher {
  public:
-  MockDataFetcher() : read_data_(false, false) {
-    memset(&test_data, 0, sizeof(test_data));
+  MockDataFetcher(WebKit::WebGamepads& test_data) : read_data_(false, false) {
+    test_data_ = test_data;
   }
   virtual void GetGamepadData(WebKit::WebGamepads* pads,
                               bool devices_changed_hint) OVERRIDE {
-    *pads = test_data;
+    *pads = test_data_;
     read_data_.Signal();
   }
 
-  void SetData(WebKit::WebGamepads& data) {
-    test_data = data;
-  }
-
   void WaitForDataRead() { return read_data_.Wait(); }
 
-  WebKit::WebGamepads test_data;
+  WebKit::WebGamepads test_data_;
   base::WaitableEvent read_data_;
 };
 
 // Main test fixture
 class GamepadProviderTest : public testing::Test {
  public:
-  gamepad::Provider* CreateProvider() {
+  gamepad::Provider* CreateProvider(WebKit::WebGamepads& test_data) {
 #if defined(OS_MACOSX)
     base::SystemMonitor::AllocateSystemIOPorts();
 #endif
     system_monitor_.reset(new base::SystemMonitor);
-    mock_data_fetcher_ = new MockDataFetcher;
+    mock_data_fetcher_ = new MockDataFetcher(test_data);
     provider_ = new gamepad::Provider(mock_data_fetcher_);
     return provider_.get();
   }
 
  protected:
   GamepadProviderTest() {
   }
 
   MessageLoop main_message_loop_;
   scoped_ptr<base::SystemMonitor> system_monitor_;
   MockDataFetcher* mock_data_fetcher_;
   scoped_refptr<gamepad::Provider> provider_;
 };
 
 TEST_F(GamepadProviderTest, BasicStartStop) {
-  gamepad::Provider* provider = CreateProvider();
+  WebKit::WebGamepads test_data;
+  memset(&test_data, 0, sizeof(test_data));
+  gamepad::Provider* provider = CreateProvider(test_data);
   provider->Start();
   provider->Stop();
   // Just ensure that there's no asserts on startup, shutdown, or destroy.
 }
 
-// http://crbug.com/105348
-TEST_F(GamepadProviderTest, FLAKY_PollingAccess) {
+TEST_F(GamepadProviderTest, PollingAccess) {
   using namespace gamepad;
 
-  Provider* provider = CreateProvider();
-  provider->Start();
-
   WebKit::WebGamepads test_data;
   test_data.length = 1;
   test_data.items[0].connected = true;
   test_data.items[0].timestamp = 0;
   test_data.items[0].buttonsLength = 1;
   test_data.items[0].axesLength = 2;
   test_data.items[0].buttons[0] = 1.f;
   test_data.items[0].axes[0] = -1.f;
   test_data.items[0].axes[1] = .5f;
-  mock_data_fetcher_->SetData(test_data);
+
+  Provider* provider = CreateProvider(test_data);
+  provider->Start();
 
   main_message_loop_.RunAllPending();
 
   mock_data_fetcher_->WaitForDataRead();
 
   // Renderer-side, pull data out of poll buffer.
   base::SharedMemoryHandle handle =
       provider->GetRendererSharedMemoryHandle(base::GetCurrentProcessHandle());
   scoped_ptr<base::SharedMemory> shared_memory(
       new base::SharedMemory(handle, true));
   EXPECT_TRUE(shared_memory->Map(sizeof(GamepadHardwareBuffer)));
   void* mem = shared_memory->memory();
 
   GamepadHardwareBuffer* hwbuf = static_cast<GamepadHardwareBuffer*>(mem);
   // See gamepad_hardware_buffer.h for details on the read discipline.
-  base::subtle::Atomic32 start, end;
   WebKit::WebGamepads output;
-  int contention_count;
 
-  // Here we're attempting to test the read discipline during contention. If
-  // we fail to read this many times, then the read thread is starving, and we
-  // should fail the test.
-  for (contention_count = 0; contention_count < 1000; ++contention_count) {
-    end = base::subtle::Acquire_Load(&hwbuf->end_marker);
+  base::subtle::Atomic32 version;
+  do {
+    version = hwbuf->sequence.ReadBegin();
     memcpy(&output, &hwbuf->buffer, sizeof(output));
-    start = base::subtle::Acquire_Load(&hwbuf->start_marker);
-    if (start == end)
-        break;
-    base::PlatformThread::YieldCurrentThread();
-  }
-  EXPECT_GT(1000, contention_count);
+  } while (hwbuf->sequence.ReadRetry(version));
+
   EXPECT_EQ(1u, output.length);
   EXPECT_EQ(1u, output.items[0].buttonsLength);
   EXPECT_EQ(1.f, output.items[0].buttons[0]);
   EXPECT_EQ(2u, output.items[0].axesLength);
   EXPECT_EQ(-1.f, output.items[0].axes[0]);
   EXPECT_EQ(0.5f, output.items[0].axes[1]);
 
   provider->Stop();
 }
 
 }  // namespace